Design and implementation of the air/water heat pump controller with increased coefficient of performance

A control algorithm designed to increase the economic performance of the air/water heat pump is described. The heat pump itself has very fast dynamics when compared with the heated object; therefore the controller uses static pump modeling to derive the control action. The algorithm controls the compressor in order to stabilize the temperature of water flowing out of the condenser and the expansion valve in order to minimize superheat and fulfill the superheat constraints. The algorithm provides stable operation of the heat pump and ensures increase of the Coefficient of Performance (COP) for different conditions in which the controlled device operates (in a wide range of air temperature). An average 10% improvement of COP when compared to the catalogue data of the tested pump with standard controller was achieved. The control algorithm was successfully implemented in the ecoTRONIC200 microprocessor controller.